title: Accuracy of leptin serum level in diagnosing ventilator-associated pneumonia: a case-control study.
abstract: BACKGROUND
  Undernutrition causes a reduction of body-fat mass and a decrease in the circulating concentration of leptin which impairs the production of proinflammatory cytokines and increases the incidence of infectious diseases. The main objective of this study was to determine whether leptin deficiency is a risk factor for ventilator-associated pneumonia (VAP).
  
  
  METHODS
  This prospective observational case-control study was conducted in a university ICU during a 2-year period. Patients with VAP (cases) were matched (1:1) to patients without VAP (controls) according to all the following criteria: age, gender, SAPS II, and duration of ICU stay before VAP occurrence. In all patients leptin, C-reactive protein (CRP) and procalcitonin (PCT) were measured at ICU admission, and twice a week. In addition, in cases, leptin, CRP and PCT were also measured on the day of VAP diagnosis.
  
  
  RESULTS
  Eighty-six cases were matched with 86 controls. No significant difference was found in leptin and PCT levels between cases and controls. CRP level was significantly higher on the day of VAP in cases compared with controls (99 vs. 48 mg/L, P=0.001). Combination of CRP-leptin (CRP ≥78 mg/L and leptin ≥6.2 ng/mL on the day of VAP) was significantly (P=0.009) associated with VAP in univariate analysis. Multivariate analysis identified the combination of CRP-leptin (OR [95% CI] 3.08 [1.18-8.04], P=0.003), LOD score (1.27 [1.08-1.48], P=0.003), neuromuscular-blockers use (6.6 [2.03-21.7], P=0.002), and reintubation (3.3 [1.14-9.6], P=0.027) as independent risk factors for VAP.
  
  
  CONCLUSIONS
  In our study, leptin level was not associated with VAP occurrence. Further studies are needed to confirm our results, and to define the exact inflammatory role of leptin, and its interest as a biomarker in ICU patients.
authors.affiliation: Intensive Care Unit, Calmette Hospital, University Hospital of Lille, Lille, France - s-nseir@chru-lille.fr.
authors.forename: E
authors.initials: E
authors.lastname: Parmentier-Decrucq
authors.forename: S
authors.initials: S
authors.lastname: Nseir
authors.forename: D
authors.initials: D
authors.lastname: Makris
authors.forename: B
authors.initials: B
authors.lastname: Desrousseaux
authors.forename: B
authors.initials: B
authors.lastname: Soudan
authors.forename: R
authors.initials: R
authors.lastname: Favory
authors.forename: D
authors.initials: D
authors.lastname: Mathieu
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D016022:Case-Control Studies; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000097:blood / Q000209:etiology / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000097:blood / Q000209:etiology / Q000382:microbiology; D006801:Humans; D034141:Hypoalbuminemia / Q000097:blood; D017053:Infection Control; D007362:Intensive Care Units / Q000706:statistics & numerical data; D020738:Leptin / Q000097:blood*; D008297:Male; D044342:Malnutrition / Q000097:blood; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000097:blood* / Q000382:microbiology / Q000517:prevention & control; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015300:Ventilator Weaning
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D020738:Leptin; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide